Many scientists argue that even current consumption levels are not
sustainable (Daily and Ehrlich, 1992; Rees, 2006). The global Ecological
Footprint/capita exceeded global Biocapacity/capita around 1978. As of
2011, humans were using 135% of the resources that can be sustainably
generated in one year (Ecological Footprint, 2011). Based on this estimate
of the degree of current overshoot, we conclude that a 35% increase
in the technical efficiency of global production would allow the
global Ecological Footprint to be brought backwithin global Biocapacity.
This degree of technical improvement appears to be feasible (von
Weizsacker et al., 2009). If this degree of technical improvement could
be achieved, then the global GDP of $67 trillion that is required to provide
a welfare-maximizing GDP/capita of $7000 for 9.6 billion people
may be sustainable. Once reached, continuing improvements in environmental
protection, full employment (distributional equity), and
product quality would allow the GPI/capita to rise without the need
for further increases in global GDP. It may be possible to increase economic
welfare without having to grow GDP, as recently seen in the
state of Maryland (King, 2012).